1. Field of the Invention
The present invention concerns an apparatus and method for rounding fibre ends of brushes, whose fibres are made of thermoplastic material, more particularly tooth brushes, with a treatment surface, which is moved relatively and transversely in relation to the fibre ends, with which the fibre ends are in contact.
2. Related Technology
During the manufacturing of brushes, after the brush fibres have been inserted or formed in the brush body, the fibres are cut at their free ends in such way that they are situated in one and the same plane. Subsequently, the cut fibre ends must be rounded to remove burrs and sharp edges. Considerable efforts are applied to the quality of the rounding of the fibres of tooth brushes as well as hair brushes, which come in contact with sensitive skin.
Consequently, known brush manufacturing machines comprise several rounding steps through which the brushes successively pass, and in which the fibre ends are put in contact with grinding tools which operate from different directions in order to exert a friction on the brush fibres in all directions. With a view to obtain a particularly high quality of the rounding, which is desired for tooth brush, the fibre ends are subsequently polished. Such final treatment of the brushes can require five to ten treatment steps which therefore constitute an essential part in the total cost of the brush manufacturing. Moreover, a lot of dust is produced which is a problem factor in the final treatment of the brushes.
The rounding is problematic with the fibre ends of those brushes of which the fibres are provided with a profiled cut as a result of which the fibre ends are not situated in one and the same plane. The short fibres are difficult to be reached by the grinding elements. In order to treat them too, the long fibres must previously be kept away by retainers or such like. Devices, with which profiled tooth brushes can be treated are for example described in DE 4 425 231 A1 or DE 4 138 777. These devices are particularly expensive.
This invention aims at a device for rounding fibre ends of brushes and which guarantees at a low cost a particularly good quality with less grinding dust.